关于json的操作 jsonArray---jsonObject

Json-lib使用——JSONObject与JSONArray

1.从Object到String

要先用Object对象构造一个JSONObject或者JSONArray对象，然后调用它的toString()方法即可

（1）示例一

1Bookbook=newBook();

2book.setName("Java");

3book.setPrice(52.3f);

4JSONObjectobject=JSONObject.fromObject(book);

5System.out.println(object.toString());

（2）示例二

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1Bookbook=newBook();

2book.setName("Java");

3book.setPrice(52.3f);

4

5Bookbook2=newBook();

6book2.setName("C");

7book2.setPrice(42.3f);

8Listlist=newArrayList();

9list.add(book);

10list.add(book2);

11JSONArrayarry=JSONArray.fromObject(list);

12System.out.println(arry.toString());

13//结果如下：

14[{"name":"Java","price":52.3},{"name":"C","price":42.3}]

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2.从String到Object

要先用String对象构造一个JSONObject或者JSONArray对象

(1)示例一

1Stringjson="{name:'Java',price:52.3}";

2JSONObjectobject=JSONObject.fromObject(json);

3System.out.println(object.get("name")+""+object.get("price"));

(2)示例二

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1Stringjson="[{name:'Java',price:52.3},{name:'C',price:42.3}]";

2JSONArrayarray=JSONArray.fromObject(json);

3for(inti=0;i<array.size();i++){

4Mapo=(Map)array.get(i);

5System.out.println(o.get("name")+""+o.get("price"));

6}

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3.从String到Bean

(1)单个Bean对象

1Stringjson="{name:'Java',price:52.3}";

2JSONObjectobject=JSONObject.fromObject(json);

3Productproduct=(Product)JSONObject.toBean(object,Product.class);

4System.out.println(product.getName()+""+product.getPrice());

(2).Bean的数组

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1Stringjson="[{name:'Java',price:52.3},{name:'C',price:42.3}]";

2JSONArrayarray=JSONArray.fromObject(json);

3Product[]products=(Product[])JSONArray.toArray(array,Product.class);

4for(Productp:products){

5System.out.println(p.getName()+""+p.getPrice());

6}

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自定义封装JSON操作的类

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1packagecom.util;

2

3importjava.util.List;

4importjava.util.Map;

5

6importnet.sf.json.JSONArray;

7importnet.sf.json.JSONObject;

8

9publicclassJsonHelper{

10//从普通的Bean转换为字符串

11publicstaticStringgetJson(Objecto){

12JSONObjectjo=JSONObject.fromObject(o);

13returnjo.toString();

14}

15//从Java的列表转换为字符串

16publicstaticStringgetJson(Listlist){

17JSONArrayja=JSONArray.fromObject(list);

18returnja.toString();

19}

20//从Java对象数组转换为字符串

21publicstaticStringgetJson(Object[]arry){

22JSONArrayja=JSONArray.fromObject(arry);

23returnja.toString();

24}

25//从json格式的字符串转换为Map对象

26publicstaticMapgetObject(Strings){

27returnJSONObject.fromObject(s);

28}

29//从json格式的字符串转换为List数组

30publicstaticListgetArray(Strings){

31returnJSONArray.fromObject(s);

32}

33//从json格式的字符串转换为某个Bean

34publicstaticObjectgetObject(Strings,Classcls){

35JSONObjectjo=JSONObject.fromObject(s);

36returnJSONObject.toBean(jo,cls);

37}

38//从json格式的字符串转换为某类对象的数组

39publicstaticObjectgetArray(Strings,Classcls){

40JSONArrayja=JSONArray.fromObject(s);

41returnJSONArray.toArray(ja,cls);

42}

43}